Categories can now be renamed using the pencil icon.
Attempts to rename to an existing category or a blank name is silently ignored.
Category list and items with the category are updated properly, on both user1 (who did the rename) and user2 (who didn't).
Anybody who's currently filtering to the old category will refresh to 0 items, until they click on the new category name to redo their filter.

Now that Bootstrap is embedded in the repo, I also removed one of the redundant bootstrap.min.js files from the repo.  Now we only have view/refs/bootstrap/js/bootstrap.min.js.